These studies are designed to determine the effects of several environmental contaminants on function of several organs following pre-and postnatal exposure. Emphasis will be placed on kidney (salt and water excretion, glomerular filtration rate, and organic ion transport) and liver (metabolism, biliary excretion of drugs). Effects of pesticides alone and in combination with known toxins will be determined at several ages during development. Alterations in excretory and metabolic functions of these organs will be correlated with structural changes with the ultimate goal of elucidating basic biochemical mechanisms of toxicity.